Isomerization of wet hexanes

ABSTRACT

A method to isomerize one or more wet hexanes in the presence of a catalyst comprising tungsten, zirconium and a Group VIII metal is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/371,997, filed Feb. 17, 2009, which is herein incorporatedby reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to isomerization of wet hexanes.

2. Description of the Prior Art

Current catalytic materials used for isomerization of hexanes, such asn-hexane, wet hexanes, and other hexanes, are not very tolerant towater, oxygenates and sulfur compounds. The most active industriallyemployed catalytic materials, such as, for example, platinum onchlorided-alumina, require extensive hexanes, i.e., feed, pretreatmentto completely remove water, sulfur, and oxygenates. Modern zeolite-basedcatalysts can tolerate up to about 200 ppmw sulfur and 200 ppmw water,although these are less active than most chlorided-alumina catalysts.Metal oxide-based catalytic materials are intermediate in activity andcan tolerate contaminants of sulfur and water at operating levels ofless than 20 ppmw. These catalysts are typically zirconia-based becauseof their ability to generate super acids through sulfation. Somecommercially available catalysts have water tolerances of up to at leastabout 30 ppmw. Unfortunately, while improvements to catalytic materialsand catalysts that are water tolerant have been made, no commerciallyavailable catalytic materials or catalysts operate effectively atconditions of greater than 200 ppmw water in the wet hexanes feedstream.

The hydrothermal stability of zirconia under aqueous phase reformingconditions makes zirconia an attractive material for processing otherfeed stocks having a high water content. While zirconia is, in and ofitself, an amphoteric material, the addition of tungsten or molybdenumhas been shown to generate considerable Brönsted acidity. This acidity,though transient in the absence of gas-phase hydrogen, is not generatedby the adsorption of strong acids, such as the case of sulfated zirconiaand chlorided alumina. This makes materials such as tungsten-zirconialikely to perform acid catalyzed conversions in the presence of water.The hydrothermal stability of tungsten-zirconia is alleged to be true,although this is more of an assertion than a proven fact.Tungsten-zirconia catalysts have been used for hydration of propylene,aqueous hydrolysis of esters, aqueous esterification, and the hydrationof ethylene, though the yields are low.

In the area of biofuels, the hydrogenation of glucose to sorbitolfollowed by hydrotreating of sorbitol to n-hexane often can result in ann-hexane stream containing up to about 30 weight percent water.Upgrading this n-hexane stream without the need to eliminate water wouldbe advantageous for process heat integration and simplicity.

SUMMARY OF THE INVENTION

The current embodiment teaches a method to isomerize wet hexanes. Themethod begins by introducing one or more wet hexanes into a reactorunder isomerization conditions to isomerize the wet hexanes. The wethexanes comprise water and hexanes. The reactor contains a catalystcomprising tungsten, zirconium, and a Group VIII metal. In thisembodiment the wet hexanes comprise from about 0.1 wt % to under 30 wt %water.

DETAILED DESCRIPTION

The following detailed description of various embodiments of theinvention illustrates specific embodiments in which the invention can bepracticed. The embodiments are intended to describe aspects of theinvention in sufficient detail to enable those skilled in the art topractice the invention. Other embodiments can be utilized and changescan be made without departing from the scope of the present invention.The following detailed description is, therefore, not to be taken in alimiting sense. The scope of the present invention is defined only bythe appended claims, along with the full scope of equivalents to whichsuch claims are entitled.

Catalysts useful in the process of the presently pending invention arecatalysts which comprise tungsten, zirconium, and a Group VIII metal(“Me”). Generally, the tungsten present in the final calcined catalystcomprises from 8 to about 30 weight percent, preferably 15 to about 30weight percent, of the mass of the final, calcined catalyst compositionand is in the form of metal (Me) tungstates (Me^(+a)(WO₄)⁻² _(a/2)),wherein the metal (Me) is selected from the group consisting of nickel,zirconium, and mixtures thereof.

Zirconium present in catalysts useful in this invention is primarily inthe form a zirconium oxide (ZrO₂) and is present within a range of about55 to about 90 weight percent, preferably 55 to about 85 weight percent,based on the total mass of the calcined catalyst composition.Additionally, zirconium tungstates also can be present in minorquantities, and, if present, these zirconium tungstates are notconsidered part of the zirconium oxide that is present in the catalyst.

The Group VIII metal useful for catalysts of the present invention isselected from the group consisting of nickel, palladium, platinum, andmixtures thereof. Preferably, the Group VIII metal is present in a rangeof about 0.05 to about 6 weight percent. However, the amount of GroupVIII metal present in the final calcined catalyst composition varieswith the Group VIII metal used. For example, if the Group VIII metal isnickel, nickel usually is present within a range of about 2 to 5 weightpercent, based on the mass of the total, final calcined catalystcomposition. If the Group VIII metal is palladium, palladium also ispresent in a range of about 0.1 to 1 weight percent, based on the massof the total, final calcined catalyst composition. If the Group VIIImetal is platinum, generally, platinum is present in the final calcinedcatalyst composition within a range of about 0.1 to about 1 weightpercent, based on the mass of the total, final calcined catalystcomposition.

Catalysts useful in the present invention can be prepared by combining aknown quantity of ammonium meta-tungstate and zirconium hydroxides. Thecomposition is prepared by incipient wetness techniques and thencalcined for a first time. Any calcination conditions can be used forcalcination, but, for ease of use, calcination occurs under air attemperatures within the range of about 1110° F. to 1650° F. Upon thisfirst calcination, while not wishing to be bound by theory, it isbelieved that the tungsten and zirconium react to produce a zirconiumtungstate. After the first calcination, the Group VIII metal, such asnickel or platinum can be added and the composition again is calcined.At the conclusion of the second calcination, it is believed that thecatalyst comprises zirconium oxides (ZrO₂), tungsten oxides (WO₃),zirconium tungstates (Zr/WO₄) and Group VIII metal tungstates (M/WO₄).Thus, if the Group VIII metal is nickel, nickel tungstates (Ni/WO₄) canbe formed. If any excess nickel is present and has not reacted with thetungstate, nickel oxide (NiO) also can be present.

If platinum is selected and added as the Group VIII metal, the resultantcatalyst has a similar composition to a catalyst having a similarcomposition comprising nickel. The catalyst composition compriseszirconium oxides, tungsten oxides, zirconium tungstates and platinum.However, while not wishing to be bound by theory, it is believed thatthe platinum does not react with tungstate to form a platinum tungstate.

Palladium also can work as the Group VIII metal. The amount of palladiumpresent in the final, calcined catalyst composition can be within therange of about 0.1 to about 1 weight percent palladium, calculatedeither as palladium metal or any other form of palladium.

Often, zirconium precursors which can be used to prepare the catalystcompositions further comprise hafnium as an impurity in the zirconiumcomponent. Therefore, catalysts useful in the present inventionoptionally can comprise hafnium.

Catalysts of the present invention generally have a surface area of lessthan about 100 m²/g. Preferably, the surface area of catalysts useful inthe present invention is less than or equal to about 50 m²/g. While notwishing to be bound by theory, it is believed that catalysts having ahigh surface area are more amorphous and therefore have less of acrystal structure. Further, while not wishing to be bound by theory, itis believed that a lower surface area catalyst can be more crystallineand therefore, can be more active. It is further believed that thepresence of hafnium helps inhibit or prevent crystallinity.

Prior to the isomerization reaction, the catalyst must be reduced. Anyreduction process known in the art can be employed, but reduction in thepresence of hydrogen is preferred, due to availability and ease of use.Preferably, the catalyst can be added to the reactor and can be reducedon-stream in the reactor. Generally, the catalyst can be reduced at apressure of about 200 psig and a temperature of about 700° F. Hydrogencan be fed at a rate of about 120 sccm (standard cubic centimeters perminute) and the catalyst reduction times of about 1 hour usually can besufficient. Upon reduction of the catalyst, the reactor contents can becooled to about 550° F. and the water-hydrocarbon mixture can be addedfor isomerization.

Isomerization process conditions useful in the present invention can beany conditions known to be useful to isomerize hexanes. As used in thisinvention, “hexanes” means any saturated, aliphatic hydrocarbon thatcomprises six carbon atoms. Wet hexanes are defined as hexanes thatcomprise of water and hexanes. In one embodiment the water content ofthe wet hexanes is less than 50 wt %, however it is possible that thewater content is less than 30 wt %, 25 wt %, 20 wt %, 15 wt %, or even10 wt %. In another embodiment the wt % of the water is from 0.1 wt % to30 wt %, 0.1 wt % to less than 30 wt %, 1 wt % to 30 wt %, 1 wt % to 25wt %, 1 wt % to 20 wt % or even 5 wt % to 20 wt %.

Any apparatus useful for isomerization also can be used. Any combinationof temperature and pressure can be used in order to maintain water inthe gas phase, i.e., steam. In accordance with this invention, it isessential that a substantial portion of the water present in the wethexanes be present as steam, and preferably, at least about 95 weightpercent of the water present in the wet hexanes be present as steam, andnot as liquid water, during the isomerization reaction. Preferably,pressure in the isomerization reactor is within a range of about 50 toabout 600 psig, preferably within a range of about 50 to about 300 psig,and most preferably, for optimal ease of use and reactivity, from 100 to300 psig. The hydrogen to hydrocarbon molar ratio preferably is about1:1 to about 20:1, and preferably about 3:1 to about 6:1. The liquidweight hourly space velocity (LWHSV) can be within a range of about 0.5to about 20 hr⁻¹ and preferably within a range of about 1 to about 5hr⁻¹. Generally, the reactor temperature can be within a range of about300° F. to about 700° F., preferably within a range of about 400° F. toabout 600° F., and most preferably, for ease of use and optimalreactivity, from 500° F. to 600° F.

Products of the isomerization of hexanes include, but are not limitedto, 2,3-dimethylbutane and 2,2-dimethylbutane. Preferably, due tofurther commercial applications, a higher 2,2-dimethylbutane content ispreferred.

EXAMPLES Example 1 Catalyst Preparation Catalyst A

Catalyst A was a commercially available platinum/zeolite catalyst usedfor isomerization of dry hexane streams, and was obtained from ZeolystInternational as Z-700A and was used as provided. Catalyst A containedless than 1 wt % platinum, based on total catalyst weight. The balancewas an aluminum oxide/zeolite carrier material. The catalyst was reducedon-stream at 700° F. and 200 psig for 1 hour in a 120 sccm hydrogenstream.

Catalyst B

Catalyst B was prepared by precipitation of amorphous Zr(OH)₄. Asufficient quantity of concentrated aqueous ammonium hydroxide was addeddrop-wise to a 0.25 molar aqueous solution of zirconyl chloride undervigorous stirring to obtain a final pH of 10.5-11. The zirconyl chloridecontained a hafnium impurity. The resulting slurry was aged for 1 hourunder vigorous stirring before being filtered and washed withapproximately 3 times its volume of distilled water. The filter cake wasdried in a vacuum oven for 2 days at 250° F. at approximately −7 psig.Once dry, the Zr(OH)₄ was washed a second time in approximately 3 timesits volume of distilled water to remove all or a substantial portion ofany residual chloride ions from the solid. The Zr(OH)₄ was driedovernight in a vacuum oven at 250° F. at approximately −7 psig. Tungstenwas deposited on the zirconium hydroxide via incipient wetnessimpregnation using an aqueous solution of ammonium metatungstate((NH₄)₆H₂W₁₂O₄₀.xH₂O) and was added drop-wise to the Zr(OH)₄ takendirectly from the vacuum oven. The concentration of the ammoniummetatungstate solution was adjusted to produce a final materialcontaining 19.7 wt % W. The wetted support was dried overnight in avacuum oven at 250° F. at approximately −7 psig. This dried material wascalcined in air for three hours at 1380° F. The calcined supportmaterial was sized to 35-100 mesh prior to the addition of thehydrogenation metal. Platinum was subsequently added by incipientwetness impregnation to the calcined tungsten-zirconia that had beendried overnight in a vacuum oven (250° F., ˜−7 psig) using aqueoussolutions of chloroplatinic acid at a concentration sufficient toproduce 0.5 wt % (based on the final composition) Pt material. Thecatalyst was again dried overnight in a vacuum oven (250° F., ˜−7 psig)before being calcined at 930° F. for 3 hours in air. The calcinedmaterial was again sized to between 35 and 100 mesh.

Catalyst C

Catalyst C was prepared in the same manner as catalyst B except theconcentration of the ammonium metatungstate solution was adjusted toresult in a final calcined catalyst having a tungsten loading of 26.8 wt% and the zirconyl chloride did not contain a hafnium impurity. Thechloroplatinic acid solution was also replaced with an aqueous solutionof nickel (II) nitrate of sufficient concentration to result in a finalcalcined material containing 2.9 wt % nickel.

Catalyst D

Catalyst D was prepared in the same manner as catalyst C except theconcentration of the ammonium metatungstate solution was adjusted toresult in a final calcined catalysts with a tungsten loading of 26.0 wt%. The nickel (II) nitrate solution had a concentration sufficient toresult in a final calcined material containing 5.0 wt % nickel.

Catalyst E

Catalyst E was prepared in the same manner as catalyst C except theconcentration of the ammonium metatungstate solution was adjusted toresult in a final calcined catalysts with a tungsten loading of 27.1 wt%. The nickel (II) nitrate solution had a concentration sufficient toresult in a final calcined material containing 2.9 wt % nickel.

A summary of Catalysts B, C, D, and E is presented in Table 1.

TABLE 1 Catalyst Characteristics Tungsten Hafnium Zirconia Metal ContentContent Content Content Surface Area Catalyst (wt %) (wt %) (wt %) (wt%) (m²/g) B 0.5 Pt 19.7 1.8 68.6 58.2 C 2.9 Ni 26.8 — 59.7 49.0 D 5.0 Ni26.0 — 60.1 50.2 E 2.8 Ni 27.1 — 59.7 47.8

Example 2 Isomerization of Wet Hexanes Catalyst A

Catalyst A was cooled to 550° F. before introducing a water and n-hexanefeed stream which contained 30 wt % water. Hydrogen was supplied to thereactor at a volume sufficient to produce a hydrogen to n-hexane molarratio of 5. The flow rate was adjusted to result in a liquid weighthourly space velocity (LWHSV) of 2 hr⁻¹. Liquid samples were collectedin a wet ice knock out flask every 30 minutes after the appearance ofliquid products. Results are shown below in Table 2.

TABLE 2 Results of contacting wet hexane with Catalyst A Time on2,2-Dimethylbutane 2,3-Dimethylbutane Dimethylbutanes n-HexaneConversion Collection Stream (min) Yield (%) Yield (%) Yield (%) (%) 1 00.042 0.195 0.237 0.97 2 30 0.023 0.149 0.172 0.60 3 60 0.026 0.1330.159 0.50 4 90 0.020 0.137 0.157 0.47 5 120 0.020 0.136 0.156 0.47 6150 0.021 0.135 0.156 0.48 7 180 0.020 0.139 0.159 0.49 8 210 0.0210.135 0.156 0.46 9 240 0.019 0.136 0.155 0.47 10 270 0.021 0.136 0.1570.48The data in Table 2 show yields of wet n-hexane to dimethylbutanes andconversions of wet n-hexane with a commercially available catalyst.

Catalyst B

The evaluation of Catalyst B for the isomerization of wet n-hexane wascarried out in the same manner as Catalyst A. Results are presented inTable 3, below.

TABLE 3 Results of contacting wet hexanes with Catalyst B Time on Stream2,2-Dimethylbutane 2,3-Dimethylbutane Dimethylbutanes n-HexaneCollection (min) Yield (%) Yield (%) Yield (%) Conversion (%) 1 0 9.3777.065 16.442 72.0 2 30 8.383 6.772 15.155 69.8 3 60 7.660 6.494 14.15468.0 4 90 7.481 6.464 13.945 68.0 5 120 7.026 6.385 13.411 67.7 6 1507.609 6.577 14.186 68.6 7 180 7.016 6.248 13.264 66.5 8 210 6.627 6.12312.750 65.6 9 240 5.615 5.301 10.916 60.3 10 270 6.252 6.072 12.324 65.2The data in Table 3 shows that under identical reaction conditions,Catalyst B has a higher conversion of n-hexane to dimethylbutanes, asevidenced by higher dimethylbutanes yields, than Catalyst A.

Catalyst C

Catalyst C was evaluated under the same conditions as Catalyst B, above.Reactivity results are presented in Table 4, below.

TABLE 4 Results of contacting wet n-hexane with Catalyst C Time on 2,2-2,3- n-Hexane Stream Dimethylbutane Dimethylbutane DimethylbutanesConversion Collection (min) Yield (%) Yield (%) Yield (%) (%) 1 0 0.2931.475 1.768 13.1 2 30 0.160 0.895 1.055 8.0 3 60 0.325 1.514 1.839 13.14 90 0.260 1.330 1.590 11.9 5 120 0.190 0.969 1.159 8.7 6 150 0.1770.865 1.042 7.6 7 180 0.176 0.894 1.070 8.0 8 210 0.198 0.953 1.151 8.49 240 0.157 0.816 0.973 7.4 10 270 0.149 0.745 0.894 6.6The data in Table 4 show that nickel-based catalysts, like Catalyst C,can isomerize wet n-hexane to dimethylbutanes.

Catalyst D

Catalyst D was evaluated under the same conditions as Catalyst B, above.Reactivity results are presented in Table 5, below.

TABLE 5 Results of contacting wet hexane with Catalyst D Time on Stream2,2-Dimethylbutane 2,3-Dimethylbutane Dimethylbutanes n-HexaneCollection (min) Yield (%) Yield (%) Yield (%) Conversion (%) 1 0 1.5352.452 3.987 36.2 2 30 0.615 1.385 2.000 22.4 3 60 0.625 1.315 1.940 22.04 90 0.476 1.075 1.551 19.3 5 120 0.411 0.907 1.318 17.7 6 150 0.3770.830 1.207 16.7 7 180 0.268 0.654 0.922 14.0 8 210 0.255 0.605 0.86013.0 9 240 0.241 0.574 0.815 12.6 10 270 0.260 0.626 0.886 13.3The data in Table 5 shows that nickel-based catalysts with higher nickelloadings, like Catalyst D, can isomerize wet n-hexane todimethylbutanes.

Catalyst E

Catalyst E was evaluated in the same manner as Catalyst B, above.Reactivity results are presented in Table 6, below.

TABLE 6 Results of contacting wet n-hexane with Catalyst E Time onStream 2,2-Dimethylbutane 2,3-Dimethylbutane Dimethylbutanes n-HexaneCollection (min) Yield (%) Yield (%) Yield (%) Conversion (%) 1 0 1.0463.692 4.738 33.1 2 30 0.705 2.558 3.263 24.2 3 60 0.836 2.882 3.718 27.44 90 0.745 2.528 3.273 25.0 5 120 0.683 2.316 2.999 23.1 6 150 0.6852.283 2.968 22.8 7 180 0.646 2.198 2.844 22.6 8 210 0.608 2.086 2.69421.4 9 240 0.493 1.768 2.261 19.0 10 270 0.474 1.715 2.189 18.3The data in Table 6 shows that nickel-based catalysts with lower nickelloadings, like Catalyst E, can isomerize wet n-hexane todimethylbutanes.

Example 3 Isomerization of Wet Hexanes

Catalyst B was evaluated under the conditions of Catalyst A in Example2, above, except that the reaction temperature reduced to 400° F.

TABLE 7 Results of contacting wet hexane with Catalyst B Time on Stream2,2-Dimethylbutane 2,3-Dimethylbutane Dimethylbutane n-Hexane Collection(min) Yield (%) Yield (%) Yield (%) Conversion (%) 1 0 0.083 0.488 0.5718.2 2 30 0.048 0.308 0.356 4.9 3 60 0.023 0.178 0.201 2.3 4 90 0.0100.087 0.097 0.6 5 120 0.010 0.071 0.081 0.2 6 150 0.011 0.099 0.110 0.17 180 0.013 0.103 0.116 0.2 8 210 0.011 0.100 0.111 0.3 9 240 0.0120.096 0.108 0.2 10 270 0.012 0.099 0.111 0.2The data in Table 7, Example 3, shows that at temperatures lower than inExample 2, Catalyst B can isomerize n-hexane and producedimethylbutanes.

Example 4 Isomerization of Dry Hexanes

Catalysts F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T and U wereprepared in a manner identical to Catalyst C except for a change intemperature for the first calcination step and the elimination of thefirst sieving of each catalyst prior to nickel addition. Nickel (II)nitrate and ammonium metatungstate solution concentrations were adjustedto result in the metal loadings shown in Table 8.

These catalysts were evaluated for the dry isomerization of a 5 wt %cyclohexane in n-hexane feed. Each catalyst was pretreated in the samemanner as Catalyst A. Following reduction, each catalyst was cooled to550° F. At 550° F., the cyclohexane/n-hexane mixture was fed to thereactor and the hydrogen flow rate was adjusted to result in a hydrogento hydrocarbon mole ratio of about 0.7. The LWHSV was about 17 hr⁻¹. Theresults are shown in table 8, below.

TABLE 8 Composition and initial n-hexane isomerization activity forCatalysts F through U. Initial Calcination Surface n-Hexane TungstenLoading Nickel Loading Hafnium Impurity Temperature Area ConversionCatalyst (wt %) (wt %) (wt %) (° F.) (m2/g) (%) F 18.2 3.32 — 1110 10223.8 G 16.4 2.54 — 1290 54.7 28.7 H 16.2 2.78 — 1470 48.9 21.6 I 17.02.74 1.41 930 125 2.2 J 16.4 3.18 1.38 1110 82.5 14.8 K 16.2 3.04 1.411290 66.6 20.8 L 16.9 2.33 — 1650 32.4 25.0 M 16.7 2.26 1.41 1470 41.622.3 N 16.2 2.78 — 1200 50.2 26.0 O 8.7 3.4 1.7 1110 93 1.87 P 16.1 3.11.5 1110 123 5.90 Q 20.2 2.1 1.1 1110 146 4.55 R 18.5 3.3 1.4 1110 1254.80 S 35.4 2.2 1.0 1110 113 2.94 T 43.3 3.1 1.1 1110 97 2.77 U 12.6 3.00.7 1110 125 4.95The data in Table 8 shows that isomerization activity generallyincreases with decreasing catalyst surface area. This data shows thatlow surface area catalysts generally are more crystalline and thereforemore active for the conversion of hydrocarbons.

Numerical Ranges

The present description uses numerical ranges to quantify certainparameters relating to the invention. It should be understood that whennumerical ranges are provided, such ranges are to be construed asproviding literal support for claim limitations that only recite thelower value of the range as well as claims limitation that only recitethe upper value of the range. For example, a disclosed numerical rangeof 10 to 100 provides literal support for a claim reciting “greater than10” (with no upper bounds) and a claim reciting “less than 100” (with nolower bounds).

DEFINITIONS

As used herein, the terms “comprising,” “comprises,” and “comprise” areopen-ended transition terms used to transition from a subject recitedbefore the term to one or more elements recited after the term, wherethe element or elements listed after the transition term are notnecessarily the only elements that make up the subject.

As used herein, the terms “including,” “includes,” and “include” havethe same open-ended meaning as “comprising,” “comprises,” and“comprise.”

As used herein, the terms “having,” “has,” and “have” have the sameopen-ended meaning as “comprising,” “comprises,” and “comprise.”

As used herein, the terms “containing,” “contains,” and “contain” havethe same open-ended meaning as “comprising,” “comprises,” and“comprise.”

As used herein, the terms “a,” “an,” “the,” and “said” mean one or more.

As used herein, the term “and/or,” when used in a list of two or moreitems, means that any one of the listed items can be employed by itselfor any combination of two or more of the listed items can be employed.For example, if a composition is described as containing components A,B, and/or C, the composition can contain A alone; B alone; C alone; Aand B in combination; A and C in combination; B and C in combination; orA, B, and C in combination.

CLAIMS NOT LIMITED TO THE DISCLOSED EMBODIMENTS

The preferred forms of the invention described above are to be used asillustration only, and should not be used in a limiting sense tointerpret the scope of the present invention. Obvious modifications tothe exemplary embodiments, set forth above, could be readily made bythose skilled in the art without departing from the spirit of thepresent invention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as pertains to any apparatus not materially departingfrom but outside the literal scope of the invention as set forth in thefollowing claims.

1. A method to isomerize wet hexanes comprising: a) introducing one ormore wet hexanes into a reactor under isomerization conditions toisomerize wet hexanes, wherein said wet hexanes comprise water andhexanes; and wherein said reactor contains a catalyst comprisingtungsten, zirconium, and a Group VIII metal, wherein the wet hexanescomprise from about 0.1 wt % to less than 30 wt % water.
 2. The methodof claim 1, wherein said wet hexanes comprise at least about 30 ppmwwater, based on the total mass of said hexanes and water.
 3. The methodof claim 1, wherein said wet hexanes comprise from about 30 ppmw toabout 50 weight percent water, based on the total mass of said hexanesand water.
 4. The method of claim 1, wherein said isomerizationconditions comprise a pressure and temperature sufficient to maintainsaid water in a gas phase.
 5. The method of claim 1, wherein saidisomerization conditions comprise a temperature within a range of about400° F. to about 700° F. and a pressure within a range of about 100 psigto about 300 psig.
 6. The method of claim 1, wherein hydrogen is addedto said reactor prior to introduction of said wet hexanes.
 7. The methodof claim 6, wherein the ratio of said hydrogen to said hexanes is withina molar ratio of about 1:1 to about 20:1.
 8. The method of claim 1,wherein said reactor has a liquid weight hourly space velocity of about0.5 hour⁻¹ to about 20 hour⁻¹.
 9. The method of claim 1, wherein saidcatalyst composition comprises; a) metal tungstates; b) zirconiumoxides; and c) a metal selected from the group consisting of nickel,platinum, palladium, and mixtures thereof.
 10. The method of claim 1,wherein said catalyst further comprises hafnium.
 11. The method of claim1, wherein said catalyst further comprises metal tungstates having acomposition of (Me^(+a)(WO₄)⁻² _(a/2)), and wherein the metal (Me) isselected from the group consisting of nickel, zirconium, and mixturesthereof.
 12. The method of claim 1, wherein the wet hexanes comprisefrom about 1 wt % to less than 30 wt % water.